Wavelength-controlled photocurrent polarity switching in BP-MoS2 heterostructure

Himani Jawa, Abin Varghese, Sayantan Ghosh, Srilagna Sahoo, Yuefeng Yin, Nikhil V. Medhekar, Saurabh Lodha

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

Layered 2D van der Waals semiconductors and their heterostructures have been shown to exhibit positive photoconductance (PPC) in many studies. A few recent reports have demonstrated negative photoconductance (NPC) as well that can enable broadband photodetection besides multi-level optoelectronic logic and memory. Controllable and reversible switching between PPC and NPC is a key requirement for these applications. This report demonstrates visible-to-near infrared wavelength-driven NPC and PPC, along with reversible switching between the two, in an air stable, high mobility, broadband black phosphorus field effect transistor covered with a few layer MoS2 flake. The crossover switching wavelength can be tuned by varying the MoS2 bandgap through its flake thickness and the NPC and PPC photoresponsivities can be modulated using electrostatic gating as well as laser power. Recombination-driven NPC and PPC, as supported by density functional theory calculations, allows for reversible switching. Further, gate voltage-dependent negative persistent photoconductance is well-suited for optosynaptic applications.

Original languageEnglish
Article number2112696
Number of pages9
JournalAdvanced Functional Materials
DOIs
Publication statusAccepted/In press - 20 Mar 2022

Keywords

  • 2D materials
  • black phosphorus
  • MoS
  • negative persistent photoconductance
  • negative photoconductance
  • recombination
  • van der Waals heterostructure

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